Current treatments for rheumatoid arthritis (RA) and other autoimmune diseases generally do not cure or prevent disease progression but only treat disease symptoms. Preliminary studies in collaboration with Harbor Branch Oceanographic Institute have identified a marine organism whose water soluble extracts contain an unusual immunosuppressive profile that may be therapeutically useful in RA and other diseases. We propose to isolate these immunosuppressive principals which inhibit T cell and tumor cell proliferation. Initially the crude, active material will be re-extracted with different polarity solvents and then subjected to reversed phase, ion exchange and/or partition chromatography. The activity will be identified initially using a tumor cell proliferation assay and then confirmed in a mitogen-induced T cell proliferation assay. Biological and partial chemical characterization of these active principals will indicate if the compounds are known and have therapeutic potential. These agents will provide new tools to approach disease therapy and biological pathways. The identification in Phase 1 and 2 and subsequent development of curative therapies for RA and other autoimmune diseases would be a scientific and commercial success.